C Program To Implement Dictionary Using Hashing Algorithms

return dict;

Each bucket in the hash table points to a linked list of entries. When keys collide, they are simply appended to the list at that index.

Because C requires manual memory management, every creation step ( malloc , strdup ) has a matching cleanup action. The free_dictionary function walks through every single node within every bucket chain, freeing strings and elements individually to eliminate resource leaks. Complexity Analysis Average Case Worst Case Search Deletion

unsigned long hash(const char *str, int table_size) unsigned long hash = 5381; int c; while ((c = *str++)) hash = ((hash << 5) + hash) + c; // hash * 33 + c

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Let’s build each component step by step.

In computer science, a dictionary (also known as a map, associative array, or symbol table) is a data structure that stores key-value pairs. It provides efficient insertion, deletion, and lookup operations. When implementing a dictionary in C—a language without built-in associative arrays—hashing algorithms offer the most practical and performant solution.

In the main function, notice the call to print_dictionary . Because we used Separate Chaining, you can visually see collisions. If "apple" and "banana" (hypothetically) hashed to the same index, the output would show:

#include <stdio.h> #include <stdlib.h> #include <string.h> return dict; Each bucket in the hash table

The most efficient way to implement a dictionary in C is by using a . This article provides a comprehensive guide and a complete, production-ready C program to implement a dictionary using hashing algorithms, featuring chaining for collision resolution. Understanding the Core Concepts

The index is then computed as hash(key) % table_size . Choosing a prime number for table_size further improves distribution.

insert(dict, "apple", "fruit"); insert(dict, "banana", "fruit"); insert(dict, "carrot", "vegetable");

To implement a robust dictionary in C using hashing, you should focus on three core components: a reliable hash function collision resolution strategy dynamic resizing to maintain performance. 1. Robust Hash Function (FNV-1a) For strings, the FNV-1a algorithm The free_dictionary function walks through every single node

Ideally, two different keys would never map to the same index. In reality, because the set of possible keys is usually larger than the size of the array, collisions are inevitable.

In C, the dictionary structure typically consists of:

curr = curr->next;

For simplicity and reliability, separate chaining is often preferred for general-purpose dictionaries in C, especially when the number of elements is unpredictable.

if (!dict->buckets) free(dict); return NULL;